Other Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest and Debt Expense
Incurred, Debt	$ 133	$ 119	$ 100
Incurred, Other	3	3	2
Incurred, Total	136	122	102
Interest Costs Capitalized Adjustment	(28)	(7)	(1)
Expensed	108	115	101
Other Income
Co-venturer contractual make-whole payments	0	0	7
Interest income	3	1	3
Other	3	1	2
Total other income	$ 6	$ 2	$ 12